1991 Rodeo ABS problem
 

I bought this car from a friend who knows little to nothing about it, or vehicles in general(he paid me to change his alternator, and couldn't figure out how to connect three wires on a headlight connector). It runs well and the 4WD works, but the ABS light is on along with the brake warning light. The brake warning light gets brighter when I apply the emergency brake, so I'm pretty sure that switch isn't the problem. The brake fluid is full. I have checked and cleaned the ABS sensor connector and checked the wires visually (they look fine) I have an OBD II reader, but the vehicle isn't new enough to use that. I have read here that I can connect jumpers to some wires in the left kick panel, but even if I figure out how to bring up the codes, I can't find a list of what the codes are anywhere. Any suggestions?